feat(chart): support configurable plot margins

src/demo/plotMarginControls.test.ts

@@ -0,0 +1,29 @@
+import { flushPromises, mount } from '@vue/test-utils'
+import { InputNumber } from 'ant-design-vue'
+import { describe, expect, it } from 'vitest'
+
+import App from '../App.vue'
+import { WaveformChart } from '../components'
+
+describe('plot margin demo controls', () => {
+  it('updates the chart top and bottom margins from the sidebar', async () => {
+    const wrapper = mount(App)
+    await flushPromises()
+    const chart = wrapper.getComponent(WaveformChart)
+    const controls = wrapper.get('.plot-margin-controls').findAllComponents(InputNumber)
+
+    expect(controls).toHaveLength(2)
+    expect(controls[0]?.props('value')).toBe(18)
+    expect(controls[1]?.props('value')).toBe(52)
+    expect(chart.props('plotMargin')).toEqual({ top: 18, bottom: 52 })
+
+    controls[0]?.vm.$emit('update:value', 30)
+    controls[1]?.vm.$emit('update:value', 70)
+    await flushPromises()
+
+    expect(chart.props('plotMargin')).toEqual({ top: 30, bottom: 70 })
+    expect(wrapper.get('.waveform-chart').attributes('data-plot-margin-top')).toBe('30')
+    expect(wrapper.get('.waveform-chart').attributes('data-plot-margin-bottom')).toBe('70')
+    wrapper.unmount()
+  })
+})